Dr Guerrini’s work, stretching over 25 years, has been concerned with investigating structure and function relationships in glycosaminoglycans. There are a biologically important family of structurally complex polysaccharides, which lie at the heart of many intercellular signalling processes, including those targeted in regenerative medicine and those disrupted in major diseases such as cancers and inflammatory conditions. His work also underpins our understanding of one of the lynchpins of modern medicine, the anticoagulant heparin. Highlights of Marco’s work have included the identification (in 2007-8) of toxic contaminants in pharmaceutical heparin, which had escaped the notice of regulatory authorities and lead to many deaths, and evidence exploding the myth of exquisite specificity in heparin-antithrombin interactions. Dr Guerrini ‘s talk will provide an introduction to this important class of polysaccharides, the principle methods that he uses currently, which are mainly NMR-based, but augmented by other complementary techniques, and will describe detailed structural studies of several interactions in solution. The talk will offer a rare opportunity to hear about interaction studies largely from the perspective of the saccharide ligand, which is often neglected, and will describe approaches that are highly complementary to the structural, functional and systems level studies currently being undertaken in IIB.